TightNeck
Posted: Sun May 13, 2012 10:20 am
Since I began reloading for the 450B, at the top of the challenges chart was the need to achieve consistent and adequate neck tension. The powders we use seem to shine their brightest when we can hold the bullet back until the powder gets really cooking, before the case opens up and releases it to go down the barrel. It is certainly not as easily accomplished as with smaller caliber, bottleneck cases.
Hornady's solution for this is the Taper Crimp, to be applied after the bullet is seated in the resized brass. It does a good job, doesn't scar the brass and is what most folks who reload for the 450B, use. For the most part, I have had good results with mine. My experience has been that if the bullet I am using has a cannelure, as in the case of the 200 and 225gr FTX bullets or driving band groove, as in the case of the Barnes XPB bullets, then seating the bullet to where that cannelure was almost buried at the mouth of the case and driving the taper crimp into it gave even better results.
Before I became a follower of the 450B, Wildcatter had conceived of a modification to be performed on the .45-70 Lee Factory Crimp Die that permitted using it to apply a stab crimp to the 450B instead of, or along with the Taper Crimp. It helps apply greater resistance to the bullet's movement out of the case before the case has expanded and released it as the normal part of ignition. I've made about 7 or 8 of them and there are several how-to threads on making the modification. While I can personally attest to the fact that it does it's job as designed, I can also attest to the fact that for me, a little accuracy was lost whenever I employed it and it scarred my $1.00 a piece brass to the point where the stab ring did not totally iron out from the pressure of ignition pressing the case against the chamber wall. Afterward, when re-using the case, the bullet I was seating went through a change in resistance as it squeezed past the scar ring left on the inside of the case. If the case had several stab crimps in different locations, the stutter step of seating happened at each one. That did not imbue me with confidence. For folks only interested in Minute of Deer accuracy, it is a not a big deal. Still, I need all the confidence I can get, not to mention the satisfaction of small groups. So, the scarring along with the slight hit on accuracy are the reasons mine doesn't get used much. Some folks agonize over rifle weight, spray paint colors, tacticool doo-dads, barrel length, suppressor compatibility, whatever. We all have our schisms.
A short while ago, I was participating in a thread about the Taper Crimp and out of the blue, a member who goes by the handle of LlindeX offered up one of those "Why didn't that ever occur to me?" great ideas. You can read it Here. In a nutshell, instead of driving the Taper Crimp or Stab Crimp into the case, through the case wall and into the bullet, LlindeX's idea was to make the case hold tighter to the bullet's bearing surface by sizing the case several thousandths narrower than the regular Hornady sizing die does, in the area where the bullet seats, before the bullet goes in. If you've worked with metal fitting, you've no doubt seen elasticity in action. Given the tendency for material to spring back to where it was displaced from. If you push it in to make a crimp it's first inclination once that force is removed is to spring back, losing some of the grip it just imparted. This is apparent with both the taper crimp and stab crimp. So much that I tend to over-crimp to allow for the springback. News flash: Brass springs back more than it's softer bullet made of copper or copper and lead. If however you pre-load the tension in the opposite direction, then that displacing force is the bullet stretching the case on it's way in and in that scenario, springback makes the case want to hold it's grip even more against the bullet.
It appears to be a good idea. I say "appears to be", only because I haven't had the opportunity to try it yet. I only yesterday reproduced the concept in my shop and it certainly stands up to Theory (see my signature). A short while from now, I will see how it works in Practice.
LlindeX used a .45 Colt die to do the shouldering on his cases. I do not own a .45 Colt, hence no die, but I do reload for the .45 ACP. Using his method, I successfully shouldered one of my cases and seated a .451 Barnes 275gr XPB bullet in it. The resistance between the bullet and the case was both firm and consistent throughout the entire seating stroke once I got it started. Even before following that up with a Taper Crimp, it took 7 strong smacks with an inertial puller on concrete, to get it out. Having just seen the negative effect of varying neck tension upon the .451 Barnes bullet using what was probably a powder that borders on too slow for it, I'm certainly open to giving it a try. Having seen the benefit from stoking up the pressure before letting the bullet go, which can account for an additional 100-150fps for the same charge, I am eager to try this new method since the extra velocity from the more complete combustion does not come at much of a price, save the effort to implement it. Enough historical context.
Here's a simple How-To, to implement this method yourself. I'll leave some of the details for you to flesh out and improve upon.
Even if you don't reload any 45 caliber handguns, both new and used dies can be had quite reasonably. No need to obsess over the brand. Cheap is good. Just not rusty or damaged for obvious reasons. If you have to get one of those dies and the price difference isn't too dire, get one with the same decapping stem type as longer rifle caliber dies you have. IE, Lee uses a smooth stem and all the immobilization effort for it is achieved only through compression of the collet. RCBS, Hornady, Lyman and I'm sure others use a threaded stem. It is immobilized by a combination of the threads and a collet. You will need a firm grasp upon the stem if you are to rely upon it to signal when to stop running the case up into the die. As I played around in the shop, I saw the issue of applying the TightNeck that relates to applying it to the same depth with each case we process. The sizing dies are designed for calibers where the case is significantly shorter than our 450B. Since we control how far a case goes into the die at the top of the ram stroke by virtue of how far we screw the die into the press, we can not unscrew these shorter dies far enough to permit that. So, an alternate method needs to be devised that limits that. Normally, when using a decapping/sizing die, we set it up so that the decapping stem extends far enough into the case so as to push out the primer, but not run into the top of the web in the bottom of the case. Voila! Just adjust that stem so that it does run into the web and you have your limit indicator. However, since the die is designed for short cases, the decapping stem does not go far enough down to accomplish this. All you need to do is borrow a decapping stem from a longer rifle caliber die set such as 30-06, 270, 300 Win Mag, 7mm Mag, I think you get it and it should be long enough to bottom out.
It is important to pause a moment and tell you that since we are only interested in shouldering down the portion of the case needed to cling to a particular bullet length, you will need to measure, adjust and record in your reloading log, how far to set the decapping stem for each bullet you load for and at what COL. Change to a bullet of a different length or seat it to a different COL and you'll need to re-determine and record that setting. Good news is you only have to do it once for each and it's not a discipline depending upon precision down to the thousandth.
What I did was lay my bullet alongside the case so that the overall distance of the two represented the COL I intended to seat it to and I marked a line on the case:
I then removed the stem from my die:
With the stem removed, I placed the die in my press, screwing it only one or two rotations until it felt sufficiently aligned and locked it down with the set nut. I took a processed case, lubed it up with Imperial Wax and while watching it atop the shell holder, I ran it up into the die stopping what I felt was short of the mark. There is resistance as you would expect when sizing brass, but not undue resistance. I withdrew the case and looked at where the shoulder was in realtion to the mark. I ran it back up a little further, emphasis on little, withdrew it and re-checked. I repeated the process until the shoulder was at the mark:
I ran it up one more time, stopping when I sensed I was at the point where any further would advance the shoulder past my mark. at that point, I ran the stem down until it bottomed out on the top of the web at the bottom of the case and locked it down firmly. At that point, The setup was complete. In my particular case, I had a Lee .45 ACP die, but no Lee long rifle caliber dies with appropriate length stems, so I had to improvise and use a piece of rod stock the same diameter as the Lee stem instead. Same result, but I have to de-prime my cases beforehand as the rod could not do that for me. If this works out as planned, I'll probably pick up a stem for a longer Lee die:
At this point, I was set up to run as many cases as I wanted to test the impact of the TightNeck process. Today being Mother's Day, I will in all likelihood not be able to do so until I get some free time after work this coming week, that coincides with good weather or better yet next weekend, to write the final chapter on this article.
A special shout-out to LlindeX for sewing the seed of inspiration on this.
Hoot
Hornady's solution for this is the Taper Crimp, to be applied after the bullet is seated in the resized brass. It does a good job, doesn't scar the brass and is what most folks who reload for the 450B, use. For the most part, I have had good results with mine. My experience has been that if the bullet I am using has a cannelure, as in the case of the 200 and 225gr FTX bullets or driving band groove, as in the case of the Barnes XPB bullets, then seating the bullet to where that cannelure was almost buried at the mouth of the case and driving the taper crimp into it gave even better results.
Before I became a follower of the 450B, Wildcatter had conceived of a modification to be performed on the .45-70 Lee Factory Crimp Die that permitted using it to apply a stab crimp to the 450B instead of, or along with the Taper Crimp. It helps apply greater resistance to the bullet's movement out of the case before the case has expanded and released it as the normal part of ignition. I've made about 7 or 8 of them and there are several how-to threads on making the modification. While I can personally attest to the fact that it does it's job as designed, I can also attest to the fact that for me, a little accuracy was lost whenever I employed it and it scarred my $1.00 a piece brass to the point where the stab ring did not totally iron out from the pressure of ignition pressing the case against the chamber wall. Afterward, when re-using the case, the bullet I was seating went through a change in resistance as it squeezed past the scar ring left on the inside of the case. If the case had several stab crimps in different locations, the stutter step of seating happened at each one. That did not imbue me with confidence. For folks only interested in Minute of Deer accuracy, it is a not a big deal. Still, I need all the confidence I can get, not to mention the satisfaction of small groups. So, the scarring along with the slight hit on accuracy are the reasons mine doesn't get used much. Some folks agonize over rifle weight, spray paint colors, tacticool doo-dads, barrel length, suppressor compatibility, whatever. We all have our schisms.
A short while ago, I was participating in a thread about the Taper Crimp and out of the blue, a member who goes by the handle of LlindeX offered up one of those "Why didn't that ever occur to me?" great ideas. You can read it Here. In a nutshell, instead of driving the Taper Crimp or Stab Crimp into the case, through the case wall and into the bullet, LlindeX's idea was to make the case hold tighter to the bullet's bearing surface by sizing the case several thousandths narrower than the regular Hornady sizing die does, in the area where the bullet seats, before the bullet goes in. If you've worked with metal fitting, you've no doubt seen elasticity in action. Given the tendency for material to spring back to where it was displaced from. If you push it in to make a crimp it's first inclination once that force is removed is to spring back, losing some of the grip it just imparted. This is apparent with both the taper crimp and stab crimp. So much that I tend to over-crimp to allow for the springback. News flash: Brass springs back more than it's softer bullet made of copper or copper and lead. If however you pre-load the tension in the opposite direction, then that displacing force is the bullet stretching the case on it's way in and in that scenario, springback makes the case want to hold it's grip even more against the bullet.
It appears to be a good idea. I say "appears to be", only because I haven't had the opportunity to try it yet. I only yesterday reproduced the concept in my shop and it certainly stands up to Theory (see my signature). A short while from now, I will see how it works in Practice.
LlindeX used a .45 Colt die to do the shouldering on his cases. I do not own a .45 Colt, hence no die, but I do reload for the .45 ACP. Using his method, I successfully shouldered one of my cases and seated a .451 Barnes 275gr XPB bullet in it. The resistance between the bullet and the case was both firm and consistent throughout the entire seating stroke once I got it started. Even before following that up with a Taper Crimp, it took 7 strong smacks with an inertial puller on concrete, to get it out. Having just seen the negative effect of varying neck tension upon the .451 Barnes bullet using what was probably a powder that borders on too slow for it, I'm certainly open to giving it a try. Having seen the benefit from stoking up the pressure before letting the bullet go, which can account for an additional 100-150fps for the same charge, I am eager to try this new method since the extra velocity from the more complete combustion does not come at much of a price, save the effort to implement it. Enough historical context.
Here's a simple How-To, to implement this method yourself. I'll leave some of the details for you to flesh out and improve upon.
Even if you don't reload any 45 caliber handguns, both new and used dies can be had quite reasonably. No need to obsess over the brand. Cheap is good. Just not rusty or damaged for obvious reasons. If you have to get one of those dies and the price difference isn't too dire, get one with the same decapping stem type as longer rifle caliber dies you have. IE, Lee uses a smooth stem and all the immobilization effort for it is achieved only through compression of the collet. RCBS, Hornady, Lyman and I'm sure others use a threaded stem. It is immobilized by a combination of the threads and a collet. You will need a firm grasp upon the stem if you are to rely upon it to signal when to stop running the case up into the die. As I played around in the shop, I saw the issue of applying the TightNeck that relates to applying it to the same depth with each case we process. The sizing dies are designed for calibers where the case is significantly shorter than our 450B. Since we control how far a case goes into the die at the top of the ram stroke by virtue of how far we screw the die into the press, we can not unscrew these shorter dies far enough to permit that. So, an alternate method needs to be devised that limits that. Normally, when using a decapping/sizing die, we set it up so that the decapping stem extends far enough into the case so as to push out the primer, but not run into the top of the web in the bottom of the case. Voila! Just adjust that stem so that it does run into the web and you have your limit indicator. However, since the die is designed for short cases, the decapping stem does not go far enough down to accomplish this. All you need to do is borrow a decapping stem from a longer rifle caliber die set such as 30-06, 270, 300 Win Mag, 7mm Mag, I think you get it and it should be long enough to bottom out.
It is important to pause a moment and tell you that since we are only interested in shouldering down the portion of the case needed to cling to a particular bullet length, you will need to measure, adjust and record in your reloading log, how far to set the decapping stem for each bullet you load for and at what COL. Change to a bullet of a different length or seat it to a different COL and you'll need to re-determine and record that setting. Good news is you only have to do it once for each and it's not a discipline depending upon precision down to the thousandth.
What I did was lay my bullet alongside the case so that the overall distance of the two represented the COL I intended to seat it to and I marked a line on the case:
I then removed the stem from my die:
With the stem removed, I placed the die in my press, screwing it only one or two rotations until it felt sufficiently aligned and locked it down with the set nut. I took a processed case, lubed it up with Imperial Wax and while watching it atop the shell holder, I ran it up into the die stopping what I felt was short of the mark. There is resistance as you would expect when sizing brass, but not undue resistance. I withdrew the case and looked at where the shoulder was in realtion to the mark. I ran it back up a little further, emphasis on little, withdrew it and re-checked. I repeated the process until the shoulder was at the mark:
I ran it up one more time, stopping when I sensed I was at the point where any further would advance the shoulder past my mark. at that point, I ran the stem down until it bottomed out on the top of the web at the bottom of the case and locked it down firmly. At that point, The setup was complete. In my particular case, I had a Lee .45 ACP die, but no Lee long rifle caliber dies with appropriate length stems, so I had to improvise and use a piece of rod stock the same diameter as the Lee stem instead. Same result, but I have to de-prime my cases beforehand as the rod could not do that for me. If this works out as planned, I'll probably pick up a stem for a longer Lee die:
At this point, I was set up to run as many cases as I wanted to test the impact of the TightNeck process. Today being Mother's Day, I will in all likelihood not be able to do so until I get some free time after work this coming week, that coincides with good weather or better yet next weekend, to write the final chapter on this article.
A special shout-out to LlindeX for sewing the seed of inspiration on this.
Hoot